The specifications on different low-density structures and high-Z admixtures are compared for target designs used to achieve smoother energy flux from different drivers. The experimentally realized aerogels are studied. Various characterization methods are used taking into account their heterogeneity. The physical processes in such materials under the powerful laser irradiation are discussed, in particular transparency dynamics, plasma homogenization, smoothing capability. The further applications of low-density cellulose triacetate (TAC) in the physical experiments are: possible targets for ns- and for ps-lasers, for EUV sources, EOS targets with low-density layer for pressure increase.